The Site-Directed Mutagenesis of Gastrodia Anti-Fungal Protein Mannose-Binding Sites and Its Expression in Escherichia Coli

Gastrodia anti-fungal protein (GAFP) displays strong inhibitory activity against certain fungal pathogens. Five GAFP analogues with different mutations at mannose-binding sites and the wild-type one were expressed and purified in Escherichia coli. The inhibitory analysis of the purified various GAFPs against the growth of Trichoderma viride indicates that single amino acid mutated-type GAFPs have inhibitory activity, but its activity is much less than the wild-type one. The double and triplicate amino acids mutated GAFPs have very low inhibitory activity. For the first time it was proved that GAFP mannosebinding sites play key role in anti-fungi process.